Hunting for deer requires quick decision making. Time required to make calculations can be time that a deer uses to move on to more inviting forage, leaving the hunter's field of view. Accordingly, a system that can be used in a brief moment, and without needing to take one's eye from a scope eyepiece, is advantageous.
Also, increasingly common timed shooting competitions require participants to navigate a course, while shooting at targets, some of which are human shaped. If a participant uses a laser range finder, the time to read the laser range finder and adjust the elevation knob accordingly is time lost in negotiating the course. A faster way of ranging and aiming would provide a competitor with an advantage, in finishing the course quickly.